INFLUÊNCIA DA ESTERILIZAÇÃO POR AUTOCLAVAÇÃO OU FILTRAÇÃO DA ÁGUA DO MAR NA SOBREVIVÊNCIA DE ESCHERICHIA COLI

Abstract

The processes of sterilization usually adopted to study the survival of Escherichia coli in salt waters frequently include autoclavation at 121ºC/30 minutes or filtrations through membrane filters of small porosity. Such technics may modify by distinct forms the natural quality of seawater, changing some of its components and removing important compounds for the growth of microorganisms. In this work the survival ofE. coli K12S in seawater was tested using filtered seawater through membrane filters of 0.22 µm or 0.45 µm or autoclavated seawater. The tested bacteria survived until 15 days in all conditions and it showed similar responses both in NaCl 2.5% solution and in autoclavated seawater. During this period the survival of E. coli K12S decreased progressively both in seawater filtered through 0.22 µm and 0.45 µm membrane filters. However, the reduction was greater in seawater filtered through 0.45 µm membrane, suggesting that the use of this membrane filter porosity seems to be more adequate to study the survival of E. coli in seawater.